Status and development trend of hot die forging press in China
China's accession to the WTO, the internationalization of the market and the globalization of procurement will definitely bring huge business opportunities to China's manufacturing industry, especially the "Currently Prioritized Development of High-Tech Industrialization" jointly issued by the automobile, aerospace manufacturing industry, the State Planning Commission and the Ministry of Science and Technology The Guide to Key Fields has determined that key industries that are prioritized for development in the automotive sector are mainly concentrated in the automotive parts manufacturing industry. The "miniaturization, lightweight, and high-speed" development direction of the automotive industry provides great opportunities for the development of the forging industry in China. 60% of automotive parts are produced by forging. Relevant expert analysis points out that the automobile industry in the United States, Japan, and Germany is so developed, thanks to its leading position in forging technology and equipment. In order to adapt to the needs of international competition after China's entry into the WTO, China's forging industry must arm itself with high and new technology, improve itself, and unswervingly follow the path of "precision, specialization, and modernization". ???????????????????????????? At the same time, hot die forging equipment directly determines a country's transportation and defense equipment strength. The proportion of die forgings in aerospace, high-speed locomotives, automobiles and other equipment directly determines a country's comprehensive equipment performance level. Hot die forging presses As the main forming equipment of forging, there will be huge development opportunities.
two, Brief history of the development of hot die forging press
The development of hot die forging presses began in the 1930s. In 1931, the hot forging press designed and manufactured by the American National Machinery Company (Natongal Machinery Company) was similar to the flat forging press that had been in existence for more than 100 years. It adopts rigid connection and the clutch is placed on the drive shaft. At the same time, the hot die forging press reduces the contact time between the heated forging or the blank and the die and the cooling time of the forging surface at the same time as the speed is increased. It establishes the prerequisites for more accurate forging of complex features. . Due to the increase in the number of strokes of the original hot die forging press, a series of new problems have arisen: the clutch cannot work satisfactorily, and the active pinion gear wears and breaks during the working stroke due to the continuous overload of the passive large gear. Therefore, in the 1940s, the clutch was moved to an eccentric shaft, and a safety friction clutch was provided on the flywheel. Since then, the improvement of the hot die forging press of the transmission structure has been mainly focused on improving the working characteristics of each component. At the same time, the auxiliary mechanism has been widely used.
Since the 1960s, in order to improve the accuracy of forgings, productivity and reliability of the press, to overcome the shortcomings of traditional hot die forging presses, began to seek new solutions from the structure, so that the hot die forging press has entered a variety of Development stage. Since the 1970s, the basic characteristics of the development of hot die forging presses are large-scale and automation. In the 1980s, Sumitomo Japan and Hasenclever in Germany each produced 160MN hot die forging pressure. At present, more and more enterprises require 160 MN hot die forging pressure. China Erzhong successfully manufactured a 168MN wedge hot die forging press in 2014, which is currently the largest hot die forging in the world. With the requirements of die forging production for automation, hot die forging automatic lines and multi-station automatic hot die forging presses have been rapidly developed. At the same time, microcomputers have begun to be widely used. The application of microcomputers in the control of hot die forging presses is an important direction for the development of hot die forging presses and their automation.
Countries that can manufacture large-scale hot die forging presses are mainly concentrated in the United Kingdom, Germany, Russia, the Czech Republic, Japan, France, Italy, and China. The main manufacturers and capabilities are as follows:
The main British manufacturers are MASSEY, Mitchell and Lambeition. Production capacity of 600t ~ 12000t;
The main German manufacturers are SMS (combined with EUMUCO and Hasenclever) and Schuler. Production capacity 315 ~ 12500t;
The main Russian manufacturers are the Fronies Heavy Machinery Plant, with a production capacity of 630 ~ 14000t;
The main Czech manufacturers are Lama Tolsko Machine Factory with a production capacity of 4000 ~ 8000T;
Major Japanese manufacturers include Komatsu Steel Works, Kurimoto Iron Works, and Sumitomo Metals . Production capacity of 630 ~ 16000t;
United States Major manufacturers have Nationnal Machinery, Production capacity of 300 ~ 8000t;
China National Heavy Industry Corporation, China National Heavy Industry Corporation, Shenyang Heavy Machinery Plant, Yang Forging, Green Forging, Rong Forging, etc., production capacity 630 ~ 16800t.
In China, the design and manufacture of hot die forging began in the 1960s. Before 80 years, the main manufacturing plants were China National Heavy Industry Corporation and Shenyang Heavy Machinery Plant. China Erzhong Group Corporation began designing and manufacturing hot die forging press after introducing technology from German EUMUCO company in 1978. Based on independent design and innovation, it has formed 1000-16800t hot die forging series products, and can produce hot die at the same time. Roller forging machines, edge trimmers, twisting machines, hydraulic correction machines and other auxiliary equipment and forging line automation have now become the main production bases of hot die forging in China.
three, The basic status and gap of the development of hot die forging technology in China
???????????????????????,??,??????????????????????,??????????????????????????????,????????????????,????????????????????????? Hot die forging equipment is widely used in automobile, aviation, electronics, home appliances and other industrial fields. Among them, the automobile industry, which is one of the indicators to measure a country's industrial level, is listed as the pillar of the national economy by the major industrial developed countries and emerging industrial countries in the world today. The development of the industry has dominated the development of forging technology and equipment. The development and progress of forging technology has basically been carried out around the development of the automotive industry.
The hot die forging press is a crank press. Its working principle is the same as that of a universal crank press. It uses different forms of crank slider mechanism to convert the rotary motion of the main drive into the reciprocating motion of the slider, and works by means of fixing it to the fuselage. The upper and lower molds on the table and slider realize the forming of heated metal. The die forging force required during the die forging process is mainly generated by the energy released by reducing the speed of the flywheel of the press. On the hot die forging press, various hot die forging processes such as open die forging, closed die forging, and extrusion can be completed. Multi-cavity hot die forging can be performed by manual operation or automatic transfer device. . In addition to considering the size, stroke, closing height and adjustment of the flat surface of the worktable and the bottom surface of the slider, the most important thing is to determine the working pressure of the press. At the same time, The energy consumed during swaging must be less than or equal to the maximum energy released by the press.
Modern hot die forging press is composed of main actuator, main drive, clutch, brake, fuselage, pneumatic and electronic control system, lubrication system, auxiliary mechanism, etc. Auxiliary mechanism refers to a device that expands the process use of hot die forging presses, reduces the adjustment time of presses and dies, and improves the reliability of the press. It mainly includes upper and lower feeding devices, die quick-change devices, closed height adjustment devices, and balance. Devices, flywheel brakes, overload protection devices, pressure monitoring indicators, temperature monitoring, etc.
?? ??,??????????:?????????????????????????? Currently in the global forging industry, the main types of production equipment are: steam air hammer, friction press, forging press, screw press, hydraulic press, etc. Judging from the development of forging equipment in recent years, it should be said that some backward forging equipment will be gradually phased out because they cannot meet the needs of modern production processes, such as steaming steam hammers. Friction presses due to their inherent limitations, although There are many, but in the end it is impossible to dominate. With the forging in the process of more and more forging towards warm forging, cold forging or warm and cold combined forging, some forging presses, high-energy screw presses, automatic pier forging machines, cold extrusion machines, etc. Advanced equipment is increasingly used in forging enterprises. With some large automobile groups represented by Ford, GM, Chrysler , Japan and South Korea, etc., hundreds of millions of US dollars of orders began to shift to the Chinese market for parts procurement, thereby accelerating the development of new technologies, new processes, advanced equipment, etc. Introduction and application of forging enterprises.
Hot die forging press can be divided into crank slider mechanism and crank connecting rod -wedge mechanism according to main actuators . According to the process, hot die forging pressure can be divided into general and special presses. Special hot die forging presses include multi-station hot die forging presses, double-action hot die forging presses, extrusion hot die forging presses, etc. The universal hot die forging pressure can be automated or constitute a multi-station hot die forging pressure after the automatic conveying device is set.
The earliest press structure in China is a hot die forging press with a traditional structure. Shenyang Heavy Machinery Works and China National Heavy Industry Group Corporation have manufactured more. Its structural characteristics: the slider has an elephant nose-shaped additional guide rail, and the closed height uses a wedge-shaped table. The lower ejection device realizes the action of forging parts ejected from the die by a cam -lever mechanism. In order to adapt to the working characteristics and reliability of the die forging press, the structural improvements over the years mainly include:
1) In order to avoid the erosion of the forged oxide scale on the wedge-shaped worktable and improve the flexibility of its adjustment, a closed hydraulic wedge-shaped worktable is used.
2) The hydraulic pre-tightening nut is adopted to relieve the stuffiness of the car during die forging.
3) It adopts double link, double point support link and wide link structure to improve the rigidity of the hot die forging press and the ability to withstand eccentric loads.
4) Flywheel brakes, micro-motion adjustment mechanism, quick mold changing device, silencer to reduce press noise, etc.
5) Improvements to clutches and brakes, jacking mechanisms, transmissions, lubrication systems, etc.
? 1978????EUMUCO?????????????MP???????,?????????????????????,????????????: Subsequently, China Erzhong Group Corporation began designing and manufacturing MP hot forging presses after introducing technology from German EUMUCO in 1978. It is based on traditional hot forging presses with the following structure. main feature:
1) Nominal fuselage The press body under 40MN has an overall solid structure. The transition between the column, the upper beam and the base is large and carefully polished to improve its fatigue strength. The body of the press with a nominal pressure greater than 40MN uses a combined structure, which is pre-tightened with four studs to form a closed frame.
2) The slider and its rail slider eliminate the elephant nose-shaped additional rail and adopt the X-shaped long rail structure. Because the gap of the X-rail is not affected by temperature changes, the gap of the guide rail can be adjusted to be smaller. It can be kept stable after adjustment without frequent adjustment.
3) The closing height is adjusted by using an eccentric pressure pin. The closed height adjusting device is arranged in the slider, which can prevent the intrusion of oxide scale generated during die forging, and can prevent the horizontal movement of the mold during the closed height adjustment.
4) The clutch and brake adopt a small inertia single disc floating block structure (large-press clutch is a multi-plate structure), which has the advantages of light heat, long friction block life, sensitivity, and easy replacement of the friction block when worn.
5) The connection between the flywheel and the brake disc equal to the shaft is connected by a keyless A / C sleeve, which has the advantages of convenient installation and removal and does not weaken the strength of the shaft.
6) Adopt PLC control. Due to the speed monitoring device, the speed drop of the press under different working loads can be measured, and the corresponding braking signal can be given, so that the slider can stop at the top dead center more accurately. When the flywheel speed drop exceeds the allowable value, a corresponding signal can be issued.
7) The press is equipped with a pressure display alarm, bearing temperature monitoring, lubrication monitoring, and various process interlocking and various fault displays. PLC automatic control is used to greatly improve the reliability of the work.
At present, the MP type hot die forging press has become the main structure of small and medium-sized hot die forging presses in China, and has become the standard for hot die forging. The domestic MP hot die forging press is basically manufactured according to the dual model structure. China Erzhong Group Corporation has manufactured more than 40 1000-6300t hot die forging presses and delivered them to domestic forging plants, which has greatly improved the forging level in China and has a high market share in the domestic small and medium-sized press market. In recent years, private enterprises such as Shandong have also started to produce hot die forging presses, but they are limited to 2500 tons and below. Due to insufficient technical reserves or insufficient capacity, there are also many quality problems. The main key technologies of MP hot die forging press:
1) Manufacturing technology of copper tile for press
A large number of bearing pads of the press belong to low-speed and heavy-duty. Copper tile manufacturing technology is particularly critical, especially high-speed bearing pads. Bearing bushes need centrifugal pouring, and the design clearance between bearing bushes and intermediate shafts is also a key technical capability of each company.
2) Press lubrication system
The press can work continuously, the lubrication system must work reliably, and the lubrication system can achieve reliable oil supply on the basis of fixed-point and quantitative.
3) Design technology of clutch and brake
The continuous and intermittent work of the press relies on the orderly work of the clutch and the brake. The design of the clutch and the brake can stop the top dead center after the press finishes the forging accurately. The phase of the clutch and the brake cannot be dry.
4) Chaining and monitoring of signals
The chain and monitoring of the signal of the press is an important indicator of the design level, which can ensure the safety of life and equipment. Humanized signal monitoring and alarm are necessary factors.
5) Large-scale manufacturing level
3150T is a medium-sized hot die forging press. The frame, eccentric shaft, connecting rod, slider, press pin, and intermediate shaft are the major pieces of equipment. The manufacturing level is the basis for measuring the press. The perfect manufacturing process and flaw detection technology It is an indispensable condition for ensuring the manufacture of presses.
After more than 30 years of development, China has formed the ability to design and manufacture modern hot die forging presses by itself, and has the ability to configure hot die forging pressure automation and automatic lines. China Yizhong is capable of manufacturing hot die forging pressures below 6300 tons, China Erzhong is capable of manufacturing hot die forging pressures of 1,000-16800 tons, and heavy has long exited the hot die forging press market, while a large number of private enterprises in Shandong are able to produce small and medium-sized hot die. Forging press. There are many manufacturers of forgings in China, and the number of equipment is huge. The manufacturing capacity and control level of hot die forging press equipment have basically reached or reached the level of developed countries, but the domestic hot die forging production line is generally not highly automated and the overall technology is not high. Only FAW A small number of large companies such as Shanghai, Second Automobile, ThyssenKrupp, Shanghai Aichi, Fast and so on use hot die forging press automatic lines. Most companies still use manual operation with low degree of automation; die forging of small and medium parts is still die. Forging hammers (electric night hammers) account for the majority. Moreover, manual loading and unloading and manual conveying of workpieces are commonly used, which easily cause defects such as scratches on the workpiece and poor surface quality of the forgings. The entire production line is long, the number of operators is large, the area is large, and labor costs are high. In order to improve the surface quality, Shanghai Aichi Forging Co., Ltd. arranged two robots in front of and behind the finishing machine on the 6300 ton hot forging press line to move the forgings by clamping the two ends of the crankshaft to perform parallelogram movements to maximize the surface quality of the forgings. At present, more and more companies are paying attention to quality while also focusing on production efficiency. The 6,300-ton hot die forging line put into operation by Shanghai Aichi Forging Company in 2006 has largely used robots instead of manual operations, achieving the fastest production cycle. 18 Seconds / piece.
????????????????????????????????,??????????????????????????,??????????????????,?????? 4000-12000?/??,?????????????????????? In the developed countries , most of the large-scale automotive parts die forgings use multi-station hot die forging presses as the main automatic line. The United States, Germany, and Japan basically use hot die forging presses to replace the original die forging hammers, and small and medium die forgings. Multi-station high-speed automatic hot heading machine is used, with a maximum speed of 4000-12000 pieces / hour, while China has basically no such aspects as multi-station forging and precision forging. ???????,?????????????? 175?/?.?,??????????????????????50?/?.?? The labor productivity of enterprises is low. The total labor productivity of the Japanese forging industry is 175 tons / person.year. The labor productivity of the most representative automobile forging company in China is 50 tons / person.year. The life of forging dies in China is generally low. Affected by factors such as materials, process design, forging equipment, heating, and lubrication, the life of hot forging dies in China is generally 4,000 to 6,000, while the life of foreign dies is 10,000 to 15,000. Die life is the main factor affecting the cost of forgings, and improving the life of forging dies is the common mission of forging enterprises in China. Overall, the gap between China's manufacturing technology level and developed countries is still large.
four, Future development trend of hot die forging industry
The manufacturing industry of the 21st century is moving from the traditional technology era characterized by machines to the technology era characterized by information, that is, using information technology to transform and upgrade traditional industries. Economic globalization and the integration of world markets are accelerating, continuously intensifying competition between manufacturers, and putting forward the requirements of a rapid response to the market. In line with this, the manufacturing industry has more urgent and strong requirements for automation technology and equipment. At the same time, the rapid development of microelectronics technology and information and communication technology has provided important technical support for automation. The numerical control, automation, and flexibility of industrial equipment have shown a booming trend. The current world hot die forging industry technology and equipment development is mainly reflected in the following aspects:
1, Pay attention to the refined design of products and improve the hot die forging product series. At present, large-scale hot die forging presses in China have been saturated, and small and medium tonnage equipment has a large demand and a lot of market information. Accelerating the refined design of hot die forging presses to make products more flexible to meet the requirements of "just in time production" Is an important goal at present. Press users require that all control functions of the equipment be integrated to achieve menu-based management of a full set of processes, which mainly include slider stroke adjustment, balancer air pressure adjustment, air cushion stroke adjustment, and parameter settings for various aspects of the automated control system. Thereby strengthening the competitiveness of the product.
2, Follow the world's advanced forging technology, improve product functions, and achieve product innovation. At present, domestic hot forging equipment clutches and brakes use dry pneumatic clutches, while Germany has begun to use wet hydraulic clutches, and 50 Fast Hot Forging Presses in Liaoyuan and 160MN Hot Forging Presses in Liaoyuan have been adopted. Die automation Clamping has been used extensively on the equipment, these are the next step in need of perfect design technology.
3. Adapted to the wide table press equipped with walking beam production. Due to the greatly improved modern forging production cycle, the walking beam is widely used on small and medium presses. The modern hot die forging press can perfectly match the walking beam and meet all the steps required for forging (flattening, pre-forging, Final forging, trimming, punching).
4. To meet the needs of automated production lines, develop various auxiliary facilities on the production line. Such as the development of walking beam manipulators to increase the coverage of hot die forging equipment. Optimized design of the manipulator of the roll forging machine to improve the cycle time.
5. The integrated control of the hot die forging press can realize all the control functions of all presses and dies through a single operation interface. Including fault diagnosis, fault analysis and alarm, and make equipment maintenance more convenient, and significantly increase the effective working time of the press. Realizing remote press operation monitoring through communication, field bus technology with on-site communication network, on-site equipment interconnection, interactive operability, decentralized function modules, and open interconnection network, is the development direction of hot die forging control technology, and it is obvious for the realization of automation. The driving role.
Fives, Concluding remarks
The rapid development of our country's hot die forging presses will surely push our equipment to the world, which will have great practical significance and far-reaching historical significance for the development of our country's forging business, and will also bring huge economic benefits. Hot die forging enterprises should narrow the gap with advanced countries and work hard to become a forging power country.